Mobility takes up a large portion of our energy consumption. Most cars run on fossil fuels, but in the future this needs to change to another source of energy, because of global warming and because the worldwide oil reserves are declining. It is necessary that the industry adapts to new technologies in time because if they wait too long it might be damaging for the economy, if everybody is still driving a petrol-powered car while the price of petrol has tripled compared to today.
So, what are the options? A few years ago we were introduced with hybrid cars. These cars are more economical but still use petrol. This year the Nissan Leaf and Peugeot Ion were released, completely electrical cars. Now in theory this is a good idea, but in practice we can see a lot of problems with electrical cars. Most importantly, their action radius is way too short to be used by everyone. A car like the Nissan Leaf can barely drive 120 km / 80 miles until its battery is empty and it takes TWELVE hours to recharge (there's a nice Top Gear episode about that: season 17 episode 6).
So we need a green car which doesn't take 6 days to drive from Amsterdam to Marseille or from New York to Chicago. Hydrogen is the solution here. 100% renewable (if the hydrogen is generated with green electricity) and you can fill up your car in 2 minutes. Downside: it's expensive, and hydrogen doesn't contain as much energy as petrol, which means that you need more of it in terms of volume to drive the same distance. But I think hydrogen has a better future than electricity because I don't think that batteries will ever be improved so much that you can drive an electric car 500 kilometers on one charge and then charge it in 15 minutes. Hydrogen will become cheaper once it gets big and people won't mind visiting the petrol station (hydrogen station!) a little bit more often, if they can spare their wallet and the environment with it.
Below a picture of the Honda Clarity, a concept hydrogen car: